Working piston for high-speed reciprocating compressors



Patented June 1'i7, 1930-4 GERHARD ROTHMANN,

F BERN E, GERMANY WORKING PIsToN Fort meri-SPEED nncrrnocumq connaissons Application med June 24, 1929,`Serial No There are reciprocating compressors known, wherein the inlet of the gaseous `Huid, generally air, is effected by means ofA an inlet-valve arranged in a cylindrical piston-head, to which the air is led through recesses provided in the piston-body. When this kind of fluid-regulation is utilized in high-speed compressors the considerable momentum due to the comparatively heavy valve-seat and valve-stop, between whichl the inlet valve is aranged, imposes a very `high tensile stress not only 'on the usually thin-Walled piston-head but also on the ribs which separate said piston-recesses and connect the piston-head to said piston-body.

This tensile stress involves a very considerable risk and will become all the more dangerous if the piston, as it is usually the case, is made of a material, such as cast-iron,

.20 electron-metal, aluminum-alloy or the like, whichgives a good sliding-surface but 1s of moderate tensile strength. N

According to my present invention lth1s risk is removed b attaching the valve-seat and valve-stop o the inlet-valve arranged in an annular piston-head by means of an especial connecting-memberv to the pistoni body in proximity to the gudgeon and preferably exactly in line with the axis of the piston so as to relieve the piston-headand the ribs which connect said piston-head to the piston-body of the stressy referred to and thus transmit the inertial stress due to said valve-seat and valve stop by the shortest path to the gudgeon. This connectingmember preferably vconsists of a screwthreaded shank which projectsfrom the cem trally arranged boss of the valve stop and passes through the valve-seat to be finally l D fixed to the piston-body by screwlng, that is to say that it may be screwed directly into said piston-body or secured thereto 1n any suitable manner by means of a nut.

This threaded shank may, ofzcourse, form an integral part of said valve-stop, or 1t may form a separate piece and 'be secured thereto. y The piston-head'is preferably provided withy ani'nner ring-shoulder or ledge upon which 373,256, Aand in Germany July 2, 1928.

place by said connected with the greatest ease, which is impossible in the known compressors of this class, wherein the valve-seat is generally practically permanently ixed. Y i

To further simplify the'embodiment of my invention, to transmit the inertial stress due to the valve-seat and valve-stop by the shortest path to the gudgeon the valvebody is constructed so as to merge above said gudgeon into a truncated cone whose centre line coincideswith the axis of the cylinderK and into the centre of whose minor-base the threaded end of said connecting-member penetrates.

In the accompanying drawin the improved working-piston and an ad]acent part of the cylinder of a high-speed compressor are shown in longitudinal section in which compressor a preliminary admission of the liuid to be compressed is effected by means lof inlet-ports arranged in the cylinder-Wall nddof an inlet-valve arranged in the pistonea' y/' In the piston-body 1 provided with piston-rings .2 a tubular dgeon 3 is seated and closed at each engl1 by a headed plug 4 adapted to prevent an accidental longitudinal displacement of the gudgeon' within the cylinder 5. `The gudgeon 3 is snugly journalled in the Vbushing 6 of a connectingrod 7.of'suitab1e construction. The pistonbody 1 terminates above said gudgeon in a hollow truncated cone 8 whose minor-base@ serves as an attaching-member and is there- 50 the va1ve seat isplnced and against which it fore provided with a vhole 10 situated exact- '100 'd` p1ston-body. 1'1 1der-s ace 429w1'11 be directly filled with ne nged an a`1r. Y e gisten is then reversed and simulvlded with is.- taneously erewith the ected y-a l 't' closed so` piston-bod 1.

stop limiting the movement of said valve a connecting-memberforming an integral part of said valve-stop and held in engagement` with said piston-body for releasably ,attaching said valve-seat and valve-stop sai Y said annular ledge and provided with a perforated hub, an annular inlet-valve arranged on said-valve-seat, a valve-stop havingan' annular fiange for limitin Ithe movement ottom face for contacting with the top face of Athe hub of said valve-seat, a connecting-member provided on said valve-stop to press the valveseat against and retain it on said internal annular ledge when engaging said pistonbody for releasably attaching said valve-seat and valve-stop to said valve-body Vin roximity to said gudgeon so as to transmit the inertial stress dueA toI said valve-seat and valve-stop by the shortest path to said gudgeon.

6. A working-piston for high-speed rec1procating compressors comprising a istonbody, a tubular gudgeon seated 1n sald piston-body, an attaching-member arranged on said piston-bod above said gudgeon 1n line body, piston-rmgs in sai with the axis o the cylinder and resemblin a truncated cone with upwardly directed minor-base, an annular piston-head, a plurality ofribs connecting said piston-head to rality of single ribs connectin vhsaid pistonhead to the mantle of said hol ow truncated cone, a valve-seat provided in said annular piston-head, a latannular inlet-valve arranged on said valve-seat, a valve-stop having an annular liange for limiting themovement of said inlet-valve, and a shank-shaped connecting-member integrally connected with the boss of said valve-stop and passing through said valve-seat andthe perforated minor-base of the truncated cone of said attaching-member when secured to said iston-body by a nut arran ed within said ollow ltruncated cone to e screwed against the inner face of said minor-base for releasably attaching said valve-seat and valvesto .to said valve-body in proximity to said u geon so as Ito transmit the inertlal stress ue to said valve-seat and valve-stop by the shortest path to said' gudgeon.

8. A piston for high-speed reciprocating compressors comprising a piston body, a piston ead, a plurality of ribs connecting said piston .head to said piston body, a valve seat provided in said piston head, an inlet valve arranged on said valve |sea,t,ia valve stop for limiting the movement of the valve, and' means' for releasably attaching said valve seat and 'stop to said piston b y. 9. A piston for high-speed reciprocating compressors comprising a piston body, a pis- `ton head,a valve seat providedin said piston head, an inlet valve arranged on-said valve seat, a valve stop for limiting Ithe movement ofthe valve, and means for re` leasably attaching said valve seat and stopA to said piston body.

In testimony whereof, I aiix my signature. l

GERHARD ROTHMANN. Y

said truncated cone, a valve-Seat provided in said piston-head, an annular inlet-valve arranged on said valve-seat, a valve-stop having an annular flange for limiting the movement of said inlet-valve, a connectlng-member projecting from the bottom-face of said valve-stop and secured in the centreof the minor-base ofthe truncated cone of said attaching-member for releasably attaching said valve-seat and valve-stop to said valvebody in proximity to said gudgeon so as to transmit the inertial stress due to said valveseat and valve-stop by the shortest path to udgeon.

said 7 working-piston for high-speed reciprocating compressors comprising a pistontubular gudgeon seated in sald piston-body, a hollow attaching-member arranged on said piston-body above said gudgeon in line with' the" axis of the cylinder and resemblin a hollow truncated cone having a centra y `perforated minor-base, an annularpistonhead, piston-rings in 'said 'piston-head, a plupiston-body, a 

